Method of making a reclosable bag



Dec. 31, 1968 5. J. RIVMAN ET L METHOD OF MAKING A RECLOSABLE BAGOriginal Filed Sept. 7, 1965 IN VB N C R S 54440: 1/. nay/4N 5N1? r A.clays/war nonusvs.

3,418,891 METHOD OF MAKING A RECLOSABLE BAG Samuel J. Rivman, WhitePlains, N.Y., and Henry Alan Carysforth, Wyckolf, N.J., assignors toGulf Oil Corporation, Pittsburgh, Pa., a corporation of PennsylvaniaOriginal application Sept. 7, 1965, Ser. No. 485,262, now Patent No.3,321,126, dated May 23, 1967. Divided and this application Feb. 10,1967, Ser. No. 627,242 2 Claims. (Cl. 93-35) This is a division of Ser.No. 485,262, filed Sept. 7, 1965, now U.S. Patent No. 3,321,126, issuedMay 23, 1967.

The present invention relates to plastic containers and methods formaking such containers; more particularly, this invention relates toclosable plastic containers which are easily opened and easily sealedshut again, and to methods for making such containers.

Plastic bags, particularly bags made of polyethylene, have come intogreat popularity for packaging various materials and articles. Forexample, clothing or similar articles often are packed in heat-sealedpolyethylene bags. Often a prospective purchaser desires to open the bagto inspect its contents. Because the bag is heat-sealed, it must be cutor torn open to permit this inspection. If the customer decides not tobuy the article, it will be difiicult to sell because its protective baghas been destroyed. This is true even if the torn bag is laboriouslysealed shut again by conventional methods.

Often, several perishable articles such as fruits and vegetables arepacked in one plastic bag. As pointed out above, once the bag is torn orcut open, it cannot be reclosed easily. Therefore, any articlesremaining in the bag after it is opened are unprotected fromcontamination and easily could fall out. If it were posible to easilyopen the bag without cutting or tearing it, and if it were easilyresealable, it would be convenient for the user to take a few items outof the bag, and then reseal the bag, thus maintaining the protection ofthe remaining items.

Accordingly, one object of the present invention is to provide a plasticbag which is easily opened and resealed Without the use of adhesivetape, heat-sealing, or other means requiring special equipment.

It is a further object of the present invention to provide a simple,sturdy, long-lasting reclosable plastic bag which is relativelyinexpensive to manufacture.

In the past, bags made of paper and similar materials have been providedwhich have a metallic strip across the top which can be bent over at itsends for rescaling the bag after it has been opened. However,considerable problems have been met in securing such metal strips to thebag material. Additionally, often it has been required that the stripshave considerable lateral extent so as to be easily handled by the user.This increases the amount of metal required for the strips and makesthem unduly expensive.

Accordingly, another object of the present invention is to provide arelatively inexpensive, reliable and troublefree method of securing ametal closure member to a plastic container, and to provide a metalrescaling member of substantial lateral extent with a minimum amount ofmetal.

A further object of the present invention is to provide a uniquecontainer structure which is foldable to cover and protect objects to becontained in the structure.

The drawings and description that follow describe the invention andindicate some of the ways in which it can be used. In addition, some ofthe advantages provided by the invention will be pointed out.

In the drawings:

nited States Patent FIGURE 1 is a perspective, partially broken-awayview of a plastic bag of the present invention;

FIGURE 2 is an enlarged cross-sectional, partially broken-away viewtaken along line 2-2 of FIGURE 1;

FIGURE 3 is an enlarged perspective view of the bag shown in FIGURE 1with the bag flap folded over during an intermediate step in the processof closing the bag;

FIGURE 4 is a perspective view of the bag of FIGURE 1 filled withobjects to be stored in it and sealed in accordance with the presentinvention;

FIGURE 5 is a perspective and partially schematic view of apparatus usedin the process of manufacturing containers in accordance with thepresent invention;

FIGURE 6 is a perspective, partially broken-away view of anotherembodiment of the container of the present invention;

FIGURE 7 is a view similar to FIGURE 6 of the container shown in FIGURE6 with the bag as originally sealed but partially opened; and

FIGURE 8 is a perspective view of another embodiment of the containerstructure of the present invention.

A polyethylene plastic bag 10 is shown in FIGURE 1 of the drawings. Thebag 10 is formed from a sheet 12 of thin polyethylene film which isfolded upon itself along a bottom fold line 14. The folded-togethersides of the sheet 12 are heat-sealed together at edges 16 and 18. Oneedge 19 of the sheet 12 forms one edge of the opening of the bag, and aportion 20 of the opposed side-wall of the bag 10 extends above the edge19 to form a flap.

In accordance with the present invention, a relatively thin corrugatedwire 22 is secured to the rear surface of flap 20 by means of a strip 24of plastic material such as polyethylene. Wire 22 extends across flap 20and serves as a closure member. The corrugated wire 22 is made ofrelatively malleable and inexpensive metal.

The process of closing the bag '10 is quite simple. The bag is filledwith the contents to be stored, the flap 20 is folded forwardly over theedge 19 to the position shown in FIGURE 3, is folded once more in thesame direction, and then the ends of the corrugated wire 22 are foldedover in the manner shown in FIGURE 4 so as to secure the bag shut.

Opening and reclosing the bag similarly is simple. First, the ends ofthe wire closure element 22 are unbent, the flap 20 is unfolded and thecontents are removed. The bag is reclosed in substantially the same wayas it originally was closed.

There are many advantages in the use of the corrugated wire 22 as thebag closure member. The corrugations and the relatively wideencapsulating plastic strip 24 supporting wire 24 make the wire 22 easyto grasp and bend, in much the same manner as a wide, solid metal strip,but without the relatively large amount of expensive metal which is usedin the metal strip. Furthermore, since the wire is tightly encapsulatedand protected by the plastic securing it to the fiap 20, it need not bemade of expensive corrosion-resistant metal. Additionally, the use ofwire as a closure member is uniquely adapted to automaticmass-production methods such as those described below.

The plastic bag shown in FIGURE 1 is manufactured by the novelmass-production method illustrated in FIG- URE 5. A sheet 12 ofpolyethylene film is supplied from a roll. First the film is foldedalong line 14 and then is fed over a series of drive and idler rollers28 with the rear surface of flap 20 facing upwardly.

The folded sheet 12 first passes beneath a spool 30 on which a roll ofwire 32 is stored. The spool 30 is rotatably mounted on a support shaft34. The wire 32 is unwound from the spool 30 and is fed through acorrugating device 38 which comprises a pair of loosely meshed spurgears between which the wire passes so that the wire takes the shape ofthe gear teeth. The corrugated wire 22 emerging from the corrugatingdevice 38 is laid upon the back surface of flap portion 20 of the sheet12.

The sheet 12 then passes beneath an extruding machine 40 which extrudesa thin strip 24 of heated thermoplastic material such as polyethyleneonto the back surface of fiap 20 over the corrugated wire 22, thusheat-sealing the strip 24 to the flap 20 and simultaneouslyencapsulating the corrugated wire 22 and fastening it securely to theflap 20.

A heated knife 44 and a cold knife 46 are periodically brought downtogether to form the plastic sheet 12 into bags. The heated knife 44simultaneously cuts the sheet into bagwidths and seals the edges 16 and18 together. The knife 46, which is air-pressure-actuated, cuts thematerial of the fiap along the same line as the cut made by the hotknife 44, and simultaneously cuts the wire 22.

The above method of attaching the wire closure member to the sheet 12has many advantages. It is relatively simple, inexpensive and is ideallyadapted to be performed by automated equipment. Furthermore, with theuse of corrugated wire 22 instead of solid metal strip for the closuremember, the length of the closure member contracts with the length ofthe plastic strip 24 as both strip 24 and wire 22 are cooling, thuspreventing the ends of the wire from extruding out from the sides of thebags and possibly injuring the users of the bag or snagging on the usersclothing. This extreme contraction is made possible by the corrugatedshape of the wire and is not obtained from solid metal strips.

Referring now to FIGURES 6 and 7, the bag 48 shown in these figures issubstantially the same as bag shown in FIGURES 1 through 4 except thattwo corrugated wires 50 and 52 are secured to the fiap by means of thestrip 24. Also, during the bag manufacturing process, the flap 20 isfolded down over the edge 19 and the flap 20 is heat-sealed to the frontwall 12 of the bag 48 along line 54. Typically, the bottom of this bagis left open and the bag is filled through the open bottom during thismanufacturing process. Then the bottom is sealed and the filled bag isshipped to the customer. a

In accordance with a further aspect of the present invention, when thecustomer wishes to open the bag 48, he may grasp the lowermostcorrugated wire 50 and pull outwardly as is illustrated in FIGURE 7,thus tearing through the strip 24 and allowing the customer to open thebag along the line where wire 50 has been pulled loose. Then, when thecustomer wishes to reclose the bag, the second corrugated wire 52 may beused to reclose the bag 10 shown in FIGURES 1 through 4. Thus, the novelcorrugated wire member of the present invention is used for a doublepurpose; both to make an easily-opened bag, and to make the bag easilyreclosable after it has been opened.

Referring now to FIGURE 8, there is shown another container structure 56which is an embodiment of the pres ent invention. Structure 56 may beused, for example, to wrap objects 58 such as boxes of vegetables or thelike before freezing them. Thus, the present invention is used to form aconvenient plastic wrapper which can be applied without specialheat-sealing tools or the like. The corrugated wire 22 and the strip 24are applied in the manner described above in connection with FIGURE 5.If it is desired to wrap rectangular objects, the strip is convenientlyplaced nearer one edge of the plastic sheet 12 than the other edge sothat the other edge may be folded over on the top of the object 58 andthe wrapper will properly cover the object. Then, the ends of wire 22and strip 24 are folded up and over the top of the object 58 to hold theplastic wrapper 56 in place. No adhesive tape or special sealingcompounds are required to seal the package shut.

While only two Wall bags have been shown in the illustrated embodiments,it is to be understood that side walls may be added to the bagstructures without departing from the teachings of the presentinvention. In addition, it should be understood that various differentflexible plastic materials can be used in containers made in accordancewith the present invention, including cellophane, paper and othertraditional plastic materials, as well as polyethylene and other modernmaterials. Further, wire closure elements other than corrugated wire canbe used. For example, plastic-coated wire-ties, such as are used forfastening vegetable stems together, etc., may be used either byencapsulation and heat sealing as described above, or by heat sealingalone by conventional heat-sealing procedures. Various other changes ormodifications in the embodiments described may occur to those skilled inthe art and these can be made without departing from the spirit or scopeof the invention as set forth in the claims.

We claim:

1. A method for making reclosable thermoplastic bags, said methodcomprising the steps of folding thermoplastic sheet material to formopposed side-walls of said bags and leaving an exposed edge of saidsheet to form a flap, continuously feeding said sheet past a firststation, continuously laying down a wire on said flap at said firststation, continuously feeding said sheet and said wire past a secondstation, extruding and laying over said wire and onto said flap arelatively wide sheet of heated thermoplastic material, cutting saidsheet to form said bags, and heat-sealing the edges of said bags.

2. A method as in claim 1 including the step of corrugating said wirebefore laying it down upon said flap.

References Cited UNITED STATES PATENTS 2,210,859 8/1940 Schafer 229-2,216,133 10/1940 Potdevin et al 229-65 3,148,598 9/1964 Davis 938BERNARD STICKNEY, Primary Examiner.

1. A METHOD FOR MAKING RECLOSABLE THERMPLASTIC BAGS, SAID METHODCOMPRISING THE STEPS OF FOLDING THERMOPLASTIC SHEET MATERIAL TO FORMOPPOSED SIDE-WALLS OF SAID BAGS AND LEAVING AN EXPOSED EDGE OF SAIDSHEET TO FORM A FLAP, CONTINUOUSLY FEEDING SAID SHEET PAST A FIRSTSTATION, CONTINUOUSLY LAYING DOWN A WIRE ON SAID FLAP AT SAID FIRSTSTATION, CONTINUOUSLY FEEDING SAID SHEET AND SAID WIRE PAST A SECONDSTATION, EXTRUDING AND LAYING OVER SAID WIRE AND ONTO SAID FLAP ARELATIVELY WIDE SHEET OF HEATED THERMOPLASTIC MATERIAL, CUTTING SAIDSHEET TO FORM SAID BAGS, AND HEAT-SEALING THE EDGES OF SAID BAGS.